FORMOSAT-3/COSMIC (F3C) is a joint Taiwan/US science mission for weather, climate, space weather and geodetic research. The F3C mission was successfully launched on 15 April 2006. Six identical micro satellites, each carrying an advanced GPS radio occultation (RO) receiver, a Tiny Ionospheric Photometer (TIP) and a Tri Band Beacon (TBB) were deployed. The satellites have since been raised by Taiwan's National Space Organization (NSPO) to their final orbit altitude at 800km to achieve an operational constellation of six orbital planes separated by 30 degrees. The payload science data are currently being downloaded every orbit via two NOAA TT&C stations (in Alaska and Norway) and one NSF/NASA station in McMurdo, Antarctica and transferred to the COSMIC Data Analysis and Archival Center (CDAAC) at UCAR in Boulder. The CDAAC currently processes the COSMIC science data in near real time - Ninety percent of RO profiles are delivered to operational weather centers within 3 hours of observation. CDAAC also reprocesses data in a more accurate post-processed mode (within 6 weeks of observation) for COSMIC as well as other missions including GPS/MET, CHAMP, SAC-C, and GRACE.

COSMIC is currently providing between 1000-2500 daily RO profiles in the neutral atmosphere, 1000-2500 daily electron density profiles and total electron content arcs, and TIP radiance products. The data have already demonstrated their value for operational weather forecasting, hurricane forecasting, and investigations of the atmospheric boundary layer. The data have been used extensively to test ionospheric models and their use in operational space weather models is under development. COSMIC GPS RO data also have the potential to be of great benefit to climate studies due to their demonstrated high precision and global and diurnal sampling coverage.